Impact of Limnological Variables on Waterbird Assemblage in a Tropical Lentic Ecosystem of Southern West Bengal, India

Birds are well-known bio-indicators, because of their high sensitivity to even slight changes in their surroundings. Therefore, documentation of waterbird assemblage in a water body can be a part of wetland monitoring from a sustainability perspective. The present study was carried out in Hansadanga beel (an ox-bow lake of Gangetic alluvial plain) of southern West Bengal (India) from January 2023 to December 2023 to assess the impact of limnological variables on waterbird assemblage. 35 different waterbird species from 11 families were identified from the study area, out of which 16 species (45.71%) were winter-migrants, 15 species (42.86%) were resident and 4 species (11.43%) were local-migrants. Ardeidae was the dominant family with highest Relative Diversity Index (RDi=20) followed by Anatidae (RDi=17.14). The maximum values of different diversity indices were observed in post-monsoon months due to the assemblage of winter-migrants and its lower values were recorded from summer months. Canonical correspondence analysis revealed that among the eight limnological variables, pH, total alkalinity, and nutrient levels best explained the variance in waterbird assemblages. Even though the study area has been impacted by a number of anthropogenic activities, it is still preferred by a variety of waterbird species, including winter-migrants. Hence, regular monitoring of avifauna and the environmental health by local or state authorities, through integrated management programs, will be beneficial for sustaining habitat growth.